A magnetometer survey (1.7 ha. in area) was conducted in July/August 2014 over the major part of playing fields associated with St Helena School, where installation of an all-weather playing surface was planned (CBC planning application 150562). The western and southern parts of the field are known to be occupied by Roman and late Iron Age structures, including a large Roman temple within an extended precinct wall and a smaller Roman temple near the northwestern border. The results confirmed the general pattern of occupation. Bordering Westway, the eastern part of the field in contrast showed a dense and unstructured scatter of anomalies probably caused by ferrous debris, the origin of which cannot be determined without excavation. Features of archaeological origin were present, especially at the western end. Not part of the formal assignment, but used as an evaluation opportunity for a new instrument, a ground penetrating radar survey over an area 80 by 40 m at the extreme west of the site shows additional structured features mostly distinct from those identified by the magnetometer.